Germline Aberrations of PAX5 Cause Susceptibility to pre-B cell Acute Lymphoblastic Leukemia

A novel heterozygous germline variant, c.547G>A (p.Gly183Ser), in the paired box protein encoding gene, PAX5, was found to segregate with disease in two unrelated kindreds with autosomal dominant pre-B cell acute lymphoblastic leukemia (ALL). Leukemic cells from both families exhibited 9p deletion, with loss-of-heterozygosity and retention of the mutant PAX5 allele at 9p13. Two additional sporadic ALL cases with 9p loss demonstrated PAX5 Gly183 substitution in the leukemic cells. Functional and gene expression analysis of the PAX5 germline variants demonstrated reduced transcriptional activity. These data extend the role of PAX5 alterations in the pathogenesis of pre-B ALL, and implicate PAX5 in a novel syndrome of germline susceptibility to pre-B cell neoplasia. We analyzed 10 samples of J558 murine myeloma cells infected with MSCV-Puro-IRES-GFP (PIG) empty vector (EV; three independent replicates), MSCV-PIG Pax5 WT (WT; three independent replicates), and MSCV-PIG Pax5 G183S (Mut; four independent replicates). Cells were selected with puromycin after infection for 5-7 days, subsequently cells were sorted for GFP and IgM expression by FACS.